Fastener



FIG. 1 is a perspective view of a fastener;

FIG. 2 is another perspective view thereof;

FIG. 3 is a front view thereof, the rear view being a mirror imagethereof;

FIG. 4 is a left-side view thereof, the right-side view being a mirrorimage thereof;

FIG. 5 is a top view thereof; and,

FIG. 6 is a bottom view thereof.

Structure, environment, and boundaries shown in broken lines form nopart of the claimed design.

CLAIM The ornamental design for a fastener, as shown and described.